Centrifugal switch with integral impeller blades



Oct. 27, 1964 B. L. BRUCKEN ETAL 3,154,650

CENTRIFUGAL SWITCH WITH INTEGRAL IMPELLER BLADES Original Filed Aug. 30, 1956 3 Sheets-Sheet l INVENTORS Bmow L. BRUCKEN I52 65mm 5. Laws THE/R :ATTORNEY 06L 7, 1964 B. L. BRUCKEN ETAL 3,154,550

CENTRIFUGAL SWITCH WITH INTEGRAL IMPELLER BLADES 3 Sheets-Sheet 2 Original Filed Aug. 30, 1956 THE/K ATTORNEY United States Patent 2 Ciaims. (Cl. ZlItF-fitl) This is a division of our copending application Ser. No. 607,118, filed August 30, 1956.

This invention relates to a domestic appliance and more particularly to a waste disposal unit for grinding waste material.

An object of the invention is to provide a waste disposal unit with an impeller having vane members pivoted to the impeller, the vane members moving away from the impeller under the action of centrifugal force when the impeller is rotated.

Another object of the invention is to provide a garbage disposal unit with a reinforced rubber throat section, the throat section being supported by a metal clamping member that holds the throat section in tight engagement with the disposal shredder ring and with the lower housing of the disposal.

Still another object is to provide a closure cap that is adapted to be mounted within a sink drain member, the closure cap comprising a dome-shaped resilient portion and a rigid insert located within the dome-shaped portion, the insert cooperating with the dome-shaped portion to permit or cut off the passage of fluid through the closure cap.

A further object is to provide a stator mounting arrangement for a dynamoelectric machine, wherein certain surfaces on the stator are machined fiat and cooperate with flat surfaces on the stator housing in order to accurately position the stator within the housing.

Another object is to provide a method of attaching a relatively hard garbage disposal impeller to an electric motor drive shaft, the method including swaging soft metal into a central aperture of the impeller, machining out the soft metal to form a shaft engaging aperture, and press-fitting the shaft within the shaft engaging aperture.

Still another object is to provide a centrifugal switch for an electric motor, the switch having a housing attachable to the motor drive shaft, the housing being formed with fan blades for pulling air over the rotor and the stator of the motor when the electric motor is in operation.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred form of the present invention is clearly shown.

In the drawings:

FIGURE 1 is a sectional view of a garbage disposal arrangement made in accordance with this invention, the impeller being shown in a section taken along line 11 of FIGURE 3;

FIGURE 2 is a view line 22 of FIGURE 1;

FIGURE 3 is a sectional view taken along line 33 of FIGURE 1;

FIGURE 4 is a sectional view taken along line 4 4 of FIGURE 1;

FIGURE 5 is a view, partly in section, of a modified impeller for a garbage disposal unit made in accordance with this invention;

FIGURE 6 is a top view of the impeller shown in FIGURE 5;

FIGURE 7 is a sectional view of a modified arrangepartly in section taken along ment for positioning a stator within the housing of an electric motor;

FIGURE 8 is a sectional view of still another modified arrangement for positioning a stator within the housing of an electric motor; and

FIGURE 9 is a sectional view of the closure cap of this invention showing the closure cap in a closed position.

The garbage or waste disposer of this invention as shown in FIGURE 1 comprises an upper housing id, and a lower impeller housing 12 to which is attached an electric motor housing 14. The upper housing it) is preferably made of a reinforced elastomeric material. The material may be of rubber reinforced with cord 16 that may be of nylon or any other suitable reinforcing material. The upper rubber housing it) is fixed to the impeller housing 12 by means of a stainless steel clamping ring 13 that conforms to the outer contour of the rubber housing. A shredder ring generaily denoted by reference numeral 29 is held in place between the impeller housing 12 and the clamping ring 18. The shredder ring has a lower flanged portion 22 that rests on and fits within a groove formed in the impeller housing as shown. The clamping ring as shown in FIGURE 1 has an outwardly directed flanged portion 24 that overlies a portion of the rubber housing 10 and also overlies an upper portion of impeller housing 12. A plurality of bolts 26 engage tapped openings in the impeller housing to hold the clamping ring 13, the rubber housing 10 and the shredder ring 20 in fixed relationship with impeller housing 12. It should be noted that the clamping ring 18 is provided with a second flanged portion 23 that overlies a part of the rubber housing it and which holds the rubber housing in tight engagement with the top portion of the shredder ring 2%. The clamping ring 18 extends somewhat above the top edge of the shredder ring and operates together with the reinforced rubber throat section to prevent the puncturing of the side walls of the upper housing by bones or the like that may be deposited within the garbage disposer.

The rubber housing it is provided with an integral conduit portion 3% that may be connected with the drain conduit of a dishwasher or the like. A pair of rubber flaps 32, one of which is shown, are formed integrally with the housing It? and are disposed at opposite sides of the intersection of conduit 36 and the housing it). When it is desired to use the drain connection 30, the portion 34 of the rubber housing is punctured out in order to connect the conduit 3%) with the interor of rubber housing 10. When the portion 34 is punched out, the rubber flaps 32 operate to prevent the passage or" waste material and water from being thrown into conduit 3t) as the waste material and water is thrown along the inner periphery of housing 16*.

The shredder ring 2% is provided with a plurality of lower teeth 36, as shown in FIGURES 1 and 3, the spaces between the teeth providing drain apertures for ground waste material and water. The shredder ring also is provided with one or more cutting teeth 38 that extend the entire length of the shredder ring. The cutting teeth 38 cooperate with an impeller generally denoted by reference numeral 41': and located partially within a chamber 42 formed in impeller housing 12. The chamber 42 communicates with a conduit portion id that is used as the drain connection for the garbage disposal unit. The impeller so comprises an intermediate portion 46 that is provided with a pair of upstanding ribs 48. One of the ribs is integrally formed with an upstanding tang 56 while the lower portion of the impeller is provided with ribs 52. The intermediate portion at of the impeiler is provided with a plurality of apertures 5'4 that are of a larger diam- 3 eter at the bottom portion of the impeller and which taper to a smaller diameter at the top portion of the 1mpeller. Preferably, the impeller is cast into the shape shown in FIGURES 1 and 3 and the apertures 54 are formed during the casting operation.

The impeller 41 is connected with a drive shaft 55 of an induction motor generally designated by reference numeral 56. This connection is made by swaging a quantity of soft metal material such as aluminum into the central aperture 58 of the impeller to form a soft metal insert 61) therein. The central aperture 58 of the impeller is preferably cast to a diameter greater than that of shaft 55 and may be roughened or made irregular to insure a good gripping action between the impeller 41 and in sert 611. The soft metal insert 61) after being swaged into the impeller 41 is machined out to form a central aperture 62 that is of a diameter slightly less than the outside diameter of shaft 55. The shaft 55 may be knurled or splined and the metal insert is then pressfitted on the shaft 55 with the shaft engaging aperture 62 tightly engaging the knurled or splined portion of the shaft.

The shaft 55 of electric motor 56 is supported within a conventional bearing 64- located in a downward extension 66 of impeller housing 12. The lower end of shaft 55 is splined to a rotor 68 of the induction motor 56. A conventional sealing bearing 71? seals the chamber 42 from the bearing 64 and a pipe or conduit 72 is connected between a chamber 74 and the outside of the garbage disposer in order to provide a drain connection for fluid that might leak past bearing seal 70 into chamber 74.

The induction motor 56 is provided with a stator that includes a laminated core 76 and a stator winding 78. The laminated core 76 is held together by rivets 79 located circumferentially of the stator and having rivet heads $11. The stator is preferably held in fixed relationship with the impeller housing 12 by a plurality of bolts 82 that pass through the stator core 76 and which are threaded into impeller housing 12. The stator core is accurately positioned with respect to the longitudinal axis of the impeller housing 12 by machining flat the top surface of rivet heads 80 and by machining smooth the cylindrical surface 86 on stator core 76. The impeller housing 12 has boss portions 88 located at circumferentially spaced points around the housing. The boss portions 88 are machined fiat along lower surfaces 911 and perpendicular to the longitudinal axis of impeller housing 12. A surface 92 formed in lower housing 12 is machined to form a cylindrical smooth surface located parallel to the longitudinal axis of the impeller housing 12. The circumferentially extending smooth surface 92 and the surface 86 when in engagement cooperate to position the stator with its longitudinal axis coinciding with the longitudinal axis of the impeller housing 12. The flat surface at the top of each rivet head 81 also cooperate to accurately position the stator core 76 when the flat surface is in engagement with the flat surface 90 on the bosses 88 of impeller housing 12. These fiat surfaces are held in tight engagement with one another by the bolts 82 which, when tightened, force the stator core 76 into tight engagement with impeller housing 12 along the above-mentioned flat surfaces.

A modified arrangement for positioning the stator core of a dynamoelectric machine in relation to a housing is shown in FIGURES 7 and 8, wherein the same reference numerals as used in FIGURE 1 denote the same or similar parts. In FIGURE 7 the stator core 76 is machined flat along surface 94 and smooth along surface 96, the

surfaces cooperating with complementary flat and smooth surfaces formed on impeller housing 12. This type of stator mount may be used with a type of stator having a solid core or with a type having a laminated core wherein the rivets are disposed inwardly from the machined edge 94. In FIGURE 7 the smooth Surface 96 is machined circumferentially of core '76 and is cylindrically shaped. The cooperating surface on impeller housing 12 is likewise smooth but cylindrically shaped.

In FIGURE 8 the rivet head 81 is provided with a top flat machined surface 98 and with a second smooth machined surface 11111. The machined surfaces 9% and 11th cooperate with flat and smooth machined surfaces formed on impeller housing 12. In this arrangement the surface 11111 is smooth but forms an arc of a clrcle and the surface 111511 may be machined smooth by turning the; surface on a lathe or the like. A third flat surface 162' may also be machined on rivet head 81 to cooperate with: a fiat surface on impeller housing 12'. With this arra ment the stator core 76 is accurately positioned with re-- spect to impeller housing 12 in a fashion slullar t t positioning of stator 76 in FIGURE 1.

The electric motor 56 as shown in FIGURE 1 is pro-' vided with an inner housing 1% and an outer housin 14. The inner housing may be fixed to the stator core 76 by means of bolts 82 and rivets 79. The outer hou ing 14 is fixed to the inner housing 1tl4 by means of one or more screws 1%. A centrifugal switch generally de noted by reference numeral has a part secured to the drive shaft 55 of the electric motor. The centrifugal switch 111 comprises a housing 112 that is press-fitte or otherwise secured to shaft 55 for rotation therewit A transverse member 114- extehds across the housing 112 and fits within slots 113a formed in the legs 113 of the housing, as shown in FIGURE 1. The transverse member 114 is preferably made of spring steel and is bowed downwardly, as shown. A pair of centrifugal weights 116 are suitably secured to spring metal member 114 as shown and tend to move the spring metal member upwardly against its inherent resiliency and out of its bowed condition to a substantially flat condition when the shaft 55 is rotated at some predetermined speed. The ends o member 114 move outwardly through slots 113r'z tq some extent when the weights 116 move upwardly. A button or bearing 114a made of nylon or other suitable mater-lat is secured to a contact arm 123 and has a top portion engaging a central protuberance formed on transverse mem ber 114, as shown. It will be apparent that the central protuberance on member 114 rotates on the top surface of button 114a when shaft 55 is rotated. I;

The contact arm 123 carries an electrical contact 120 and is secured to a sheet of insulating material that is in turn suitably secured to housing 104. A second contact 122 is suitably supported above insulator 125 and cooperates with contact 120. The contact arm 123 is made of a spring metal such as spring steel and, due to its own resiliency, normally holds contact120 away from relatively fixed contact 122. The spring bias of member 114, however is sufficient to hold contact arm' 123 down-' wardly to a position wherein contacts 120 and 122 are in engagement. The contact arm 123 and contact 122 are electrically connected with post 126.

When shaft 55 is rotated at some predetermined speed, the weights 116 operate to elevate the central protuberance of member 114, thus moving the protuberance away from the button 114a. In this position the member 114 is substantially flat and the ends of member 114 move outwardly through slots 113a to some extent. With the central protuberance out of engagement with button 114a, the contact arm 123 moves upwardly under its own resilience, thereby moving contact 120 away from contact 122. It should be noted that the inherent resiliency of the member 114 in its bowed natural condition of FIGURE 1 is sufficient to hold contact arm 123 down when the shaft 55 is not rotating. The hous ing 112 of the centrifugal switch is provided with integral fan blades 128 that operate to circulate cooling air over the rotor and stator of the induction motor when the motor isin operation. In order to provide a flow path for air being drawn through the housing of the electric motor by fan blades 128, the impeller housing 12is formed with one or more air passages 129, while the housings 104 and 14 are, respectively, provided with air passages 130 and 132. The contacts 120 and 122 of centrifugal switch 110 are used to cut out the starter or phase winding of the induction motor 56 when the rotor shaft 55 reaches some predetermined rotational speed. The circuit connections between the centrifugal switch 11tland the induction motor 55 are not shown as they are well known to those skilled in the art.

The upper portion of rubber housing is provided with a metal ring 134 bonded or otherwise secured to a flanged portion of the rubber housing. The metal ring 134 and the disposal are supported by clamping means generally denoted by reference numeral 136.

The clamping means includes an annular metal ring 140 that encircles a downwardly cylindrically shaped portion of a tubular sink drain member 145. A second annular metal ring 142 encircles the lower portion of sink drain member 146 and is disposed above ring 140. A flexible sealing member 143 made of rubber or the like is interposed between the ring 142 and a flanged portion of drain member 146. A plurality of bolts 138, one of which is shown, are threaded into ring 1411 with the heads of the bolts facing ring 1 12. Each bolt is provided with an L-shaped clamping member 14-5, the two legs of the member abutting clamp 134 and ring 142 respectively. The clamping member 145 is held in place by a nut threaded on the bolt 138 as shown. The above described connection is made by first assembling the sink drain member 146 within a drain opening in a sink. The flexible member 14-3 and the metal ring M2 are then slipped onto the sink drain member. The metal ring 140 carrying the bolts 13% is then slipped over the lower end of sink drain member 146. A snap ring 147 is then slipped on the member 145. The snap ring fits within a circumferentially extending inwardly bent portion of member 146 and engages the underside of ring 1411 as shown. With the parts in this assembled position, the bolts 13% may be rotated and move upwardly due to the threaded connection with ring 1411. In moving upwardly the bolt heads move rings 142 and 143 into tight engagement with the flanged portion of member 144 and member 144 is clamped between drain member 1% and flexible member 143. With this operation complete the open end of housing 10 is slipped over the lowermost portion of drain member 145. The clamps 145 are then slipped onto bolts 138 and are drawn up tight against ring 134 and ring 14.0 by the nuts as shown. With this arrangement the disposal unit is securely fixed to the bottom of the sink.

A stopper generally denoted by reference numeral 148 is located within sink drain member 146 and has an upper handle portion and a dome-shaped portion 151} that merges into a cylindrical portion 152 which tightly engages the walls of sink drain member res. The sink drain member 146 is provided with circumferentially extending ledge that supports the lowermost portion of stopper 148 as shown. The stopper 148 is preferably made of an elastomeric material such as rubber and carries a stainless steel plate 154-. The stainless steel plate has a central aperture 156 while the dome-shaped portion of the stopper 148 is provided with a plurality of circumferentially spaced apertures 158. When the stopper is in the position shown in FIGURE 1, water draining down into sink drain portion 146 may pass through apertures 158, aperture 156 and through a central aperture formed in rubber guard 160 and hence into the interior of rubber housing 10.

The rubber guard 160 preferably has a plurality of radially extending slits (not shown) extending outwardly from the central aperture. The outer peripheral edge of guard 160 fits within a groove formed by bending the sink drain to the shape shown in FIGURE 1. The domeshaped portion 150 of stopper 148 is adapted to be collapsed and remain in the position shown in FIGURE 9. In this position an annular rib 152 integral with the dome-shaped portion of the stopper engages the stainless steel plate and closes a drain path ordinarily provided by apertures 158 and aperture 156. The stopper 148 may be removed from within the sink drain portion 146 by grasping the top portion of the stopper and removing the stopper from within the sink drain. The stopper when in position in the sink drain 146 may be closed by simply pressing downwardly on the top portion of the stopper in order to collapse the dome-shaped portion and thus force the annular rib 162 against the stainless steel plate 154.

A modified impeller adapted to be used with the garbage disposal unit of FIGURE 1 is shown in FIGURES 5 and 6. In these figures the same reference numeral as those used in FIGURE 1 represent the same or similar parts. The impeller 164 as shown in FIGURES 5 and 6 is cylindrically shaped and is provided with a pair of diametrically opposed slots 166. A flat sheet of spring metal 168 is secured to the top portion of impeller 164 and has end portions that extend over the slots 166. The flat spring metal sheet is secured to impeller 164 by means of a bolt 179 that also serves to hold the impeller fixed to drive shaft 55. A pair of vane members 172 are secured to the underside of spring metal member 168 by means of screws 174. The vane members 172 as shown in FIGURES 5 and 6 lie within the diametrically opposed slots 166. When the impeller 154 is rotated at high speeds, the vanes 172 move upwardly to the dotted line positions of FIGURE 5 to provide an improved grinding action. The impeller 164 is provided with a pluraiity of apertures 178 that permit the drainage of fluid and waste material from upper housing 10 into the chamber 42.

It should be noted that the conduit 44 formed in housing 12 of the disposal as shown in FIGURE 1 may be provided with a rubber connector that is formed with an integral conduit portion 182. The conduit portion 1552 may be used as a drain connection for a dishwasher or the like when the material at 184 is punched out to connect the conduit 182 with the interior of the conduit 180.

In operation, waste material that is to be ground and disposed of is deposited within the upper housing 11 of the garbage disposal. The waste material together with water passing through closure cap 148 are thrown centrifugally against the shredder ring 20 and are ground, due to the cooperation of impeller 40 and the cutting teeth 33. It should be noted that the shredder ring 211 is formed with an annular head 2%, as shown in FIG- URE 1, that extends around the shredder ring between cutting teeth 38. The head 25a prevents the shearing off of the portion of the rubber housing 15 that abuts the top rim of the shredder ring by waste material moving up on the shredder ring during the grinding operation. The ground waste material passes downwardly through the apertures formed in the impeller 41 and flows downwardly through the spaces located between teeth 36 into chamber 42. This waste material mixed with the water then flows outwardly through conduit portion 44 that is connected with a drain conduit 1% that is in turn preferably connected with a sewer line.

While the form of embodiment of the invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted, as may come within the scope of the claims which follow.

What is claimed is as follows:

1. In combination with a motor having a rotor shaft and enclosure means enclosing said shaft, a centrifugal switch comprising, a box-like sheet metal housing attached directly to the end of said rotor shaft for rotation therewith and having opposite walls in relatively fixed relationship to each other, each of said opposite walls having a slot therein, a spring metal member having opposite ends relatively freely slidably projectable through the slots in the respective opposite walls of said housing without moving said walls, a pair of weights secured to said spring metal member, said spring metal member moving from a normally bowed condition wherein said ends project through said slots afirst distance when said rotor shaft is rotated below a predetermined speed and moving to a substantially flat condition under the influence of said weights wherein said ends of said spring member project through said slots a second distance greater thansaid first distance when said rotor shaft is rotated at said predetermined speed, the position of said opposite walls remaining the same relative to each other when said spring metal member is in either said fiat condition or said bowed condition, motor switch means including a switch arm directly biasingly engaged by a portion of said spring metal member located between said Weights and a contact engageable by said switch arm when said spring metal member is in its bowed condition, said motor switch means being operable in response to the movement of said spring metal member from its bowed condition to its substantially flat condition to move said switch arm to disengage said contact, and impeller means formed as an integral extension of at least one of said opposite walls for cooling said motor, said impeller means extending toward said enclosure means and remaining a fixed spaced distance from said enclosure means when said spring metal member is in either its bowed condition or its flat condition.

2. In combination with a motor having a rotatable shaft and enclosure means enclosing said shaft, a centrifugal switch comprising, an inverted box-like sheet metal housing attached directly to the end of said shaft for rotation therewith and having integral opposite walls in permanently relatively fixed relationship to each other, each of said opposite walls having a slot therein, a spring metal member having opposite ends relatively freely slidably projectable through the slots in the respective opposite walls of said housing, said slots being sufiiciently large relative to the respective ends of said spring metal member that the said ends can project either a first or second distance through said slots without moving said walls, a pair of weights secured to said spring metal member, said spring metal member moving from a normally bowed condition wherein said ends project through said slots said first distance when said rotor shaft is rotated below a predetermined speed and moving to a substantially flat condition under the influence of said weights wherein said ends of said spring member project through said slots said second distance greater than said first distance when said rotor shaft is rotated at said predetermined speed, the position of said opposite walls remaining the same relative to each other when said spring metal member is in either said flat condition or said bowed condition, motor switch means including a switch arm directly biasingly engaged by a portion of said spring metal member located between said weights and on the opposite side of said spring metal member from said weights and a contact engageable by said switch arm when said spring metal member is in its bowed condition, said motor switch means being operable in response to the movement of said spring metal member from its bowed condition to its substantially flat condition to move said switch arm to disengage said contact, and a sheet metal impeller blade formed as an integral, radially outwardly directed extension of at least one of said opposite walls and rotatable therewith for cooling said motor, said impeller blade extending toward said enclosure means, and the plane of rotation of said impeller blade and the distance thereof from said enclosure means remaining the same when said spring metal member is in either said flat condition or said bowed condition.

References (fit ed in the file of this patent UNITED STATES PATENTS 2,460,246 Vacha Jan. 25, 1949 2,923,789 Howard Feb. 2, 1960 3,013,133 Seyfried et al. Dec. 12, 1961 

1. IN COMBINATION WITH A MOTOR HAVING A ROTOR SHAFT AND ENCLOSURE MEANS ENCLOSING SAID SHAFT, A CENTRIFUGAL SWITCH COMPRISING, A BOX-LIKE SHEET METAL HOUSING ATTACHED DIRECTLY TO THE END OF SAID ROTOR SHAFT FOR ROTATION THEREWITH AND HAVING OPPOSITE WALLS IN RELATIVELY FIXED RELATIONSHIP TO EACH OTHER, EACH OF SAID OPPOSITE WALLS HAVING A SLOT THEREIN, A SPRING METAL MEMBER HAVING OPPOSITE ENDS RELATIVELY FREELY SLIDABLY PROJECTABLE THROUGH THE SLOTS IN THE RESPECTIVE OPPOSITE WALLS OF SAID HOUSING WITHOUT MOVING SAID WALLS, A PAIR OF WEIGHTS SECURED TO SAID SPRING METAL MEMBER, SAID SPRING METAL MEMBER MOVING FROM A NORMALLY BOWED CONDITION WHEREIN SAID ENDS PROJECT THROUGH SAID SLOTS A FIRST DISTANCE WHEN SAID ROTOR SHAFT IS ROTATED BELOW A PREDETERMINED SPEED AND MOVING TO A SUBSTANTIALLY FLAT CONDITION UNDER THE INFLUENCE OF SAID WEIGHTS WHEREIN SAID ENDS OF SAID SPRING MEMBER PROJECT THROUGH SAID SLOTS A SECOND DISTANCE GREATER THAN SAID FIRST DISTANCE WHEN SAID ROTOR SHAFT IS ROTATED AT SAID PREDETERMINED SPEED, THE POSITION OF SAID OPPOSITE WALLS REMAINING THE SAME RELATIVE TO EACH OTHER WHEN SAID SPRING METAL MEMBER IS IN EITHER SAID FLAT CONDITION OR SAID BOWED CONDITION, MOTOR SWITCH MEANS INCLUDING A SWITCH ARM DIRECTLY BIASINGLY ENGAGED BY A PORTION OF SAID SPRING METAL MEMBER LOCATED BETWEEN SAID WEIGHTS AND A CONTACT ENGAGEABLE BY SAID SWITCH ARM WHEN SAID SPRING METAL MEMBER IS IN ITS BOWED CONDITION, SAID MOTOR SWITCH MEANS BEING OPERABLE IN RESPONSE TO THE MOVEMENT OF SAID SPRING METAL MEMBER FROM ITS BOWED CONDITION TO ITS SUBSTANTIALLY FLAT CONDITION TO MOVE SAID SWITCH ARM TO DISENGAGE SAID CONTACT, AND IMPELLER MEANS FORMED AS AN INTEGRAL EXTENSION OF AT LEAST ONE OF SAID OPPOSITE WALLS FOR COOLING SAID MOTOR, SAID IMPELLER MEANS EXTENDING TOWARD SAID ENCLOSURE MEANS AND REMAINING A FIXED SPACED DISTANCE FROM SAID ENCLOSURE MEANS WHEN SAID SPRING METAL MEMBER IS IN EITHER ITS BOWED CONDITION OR ITS FLAT CONDITION. 